Field of the Invention
The invention relates to an optical signal transmission device for transmitting optical signals between a number of optical signal output elements and a number of optical signal reception elements. The optical signal transmission device has at least one light-guide device to which the respective optical signal output elements and the respective optical signal reception elements are assigned, and which is combined, if appropriate, together with at least one printed circuit board serving to transmit electric signals to form a signal transmission plate configuration.
An optical signal transmission device of the type specified above is already known (see conference volume on the 3rd workshop titled xe2x80x9cOptik in der Rechnertechnikxe2x80x9d [xe2x80x9cOptics in Computer Engineeringxe2x80x9d], Dec. 8, 1998, pages 3, 4). In the known optical signal transmission device, the respective light-guide device is formed by an optical waveguide. However, only an optical point-to-point connection from one end to the other end of the respective optical waveguide is thereby rendered possible. Since such optical waveguides are disposed as a rule in a fixed fashion in the respective signal transmission plate device, it follows that no flexible configuration of optical signal output elements and optical signal reception elements is possible. Moreover, as a rule only optical signals of one wavelength are transmitted by such optical waveguides.
It is accordingly an object of the invention to provide an optical signal transmission device which overcomes the above-mentioned disadvantages of the prior art devices of this general type, which permits a flexible configuration of the optical signal output elements and the optical signal reception elements in a relatively simple way.
With the foregoing and other objects in view there is provided, in accordance with the invention, an optical signal transmission device for transmitting optical signals. The device contains light-guide layers having optically reflecting outer surfaces and formed of a material being at least low-loss for optical waveguides used for optical signal transmission. At least one electric printed circuit board for transmitting electric signals is disposed on one of the light-guide layers. The light-guide layers and the at least one electric printed circuit board form a signal transmission plate configuration. A number of optical signal output elements are disposed in the signal transmission plate configuration and have light output regions each aligned with a respective one of the light-guide layers for outputting the optical signals. A number of optical signal reception elements are disposed in the signal transmission plate configuration and have light reception regions each aligned with a respective one of the light-guide layers for receiving the optical signals. The optical signal output elements and the optical signal reception elements can be operated in a wavelength-specific fashion in each case on their own.
The object indicated above is achieved according to the invention in the case of an optical signal transmission device of the type mentioned at the beginning by virtue of the fact that the respective light-guide device contains a light-guide layer. The light-guide layer is at least low-loss for the optical waveguides used for optical signal transmission and whose outer surfaces are optically reflecting. The optical signal output elements and the optical signal reception elements are inserted into the signal transmission plate configuration such that their light output regions and their light reception regions, respectively, are aligned with the respective optical light-guide layer for outputting or receiving optical signals. The optical signal output elements and the optical signal reception elements can be operated in a wavelength-specific fashion in each case either on their own or in conjunction with transmitting or receiving units assigned to them.
The invention is distinguished by the advantage of creating an optical signal transmission device which is particularly easy to produce and has a more flexible configuration of the optical signal output elements and the optical signal reception elements than is the case with the previously known optical signal transmission device, in the case of which a single optical waveguide is used as the respective light-guide device.
The present invention therefore opens up completely new possibilities in printed circuit board and/or module engineering. The respective material or light-guide layer used as the respective light-guide device permits the transmission of several optical signals, either at the same or different wavelengths, and thereby permits the wavelength-division multiplex (WDM) transmission principle to be used. Thus, it is directly possible, for example, to use an optical signal output device to output optical signals at a multiplicity of wavelengths which are received individually by optical signal reception devices used in a wavelength-specific fashion, or else an optical signal reception device which is to a certain extent a broadband one can receive optical signals output in a plurality of provided optical signal output devices operated in a wavelength-specific fashion. In this case, the individual optical signal output elements and the optical signal reception elements can be disposed in the optical signal transmission device according to the invention at widely disparate points in the light-guide layer forming the respective light-guide device, since the optical signals output by the optical signal output elements propagate inside the light-guide layer by reflection into all regions of this layer, and can thereby be received by the optical signal reception elements disposed at any points inside the light-guide layer. Data rates of up to 10 Gbit/s can be achieved directly in the case of the optical signal transmission in accordance with the invention without external influences being exerted on the signal integrity. Crosstalk, ground bounce and other EMC problems do not arise.
The light-guide layer preferably is formed of polymethyl methacrylate (PMMA), which is a material that is not as fragile as glass but nevertheless has excellent coupling properties.
The optical signal output elements and the optical signal reception elements each have fixing elements by which the relevant optical signal output elements and the optical signal reception elements of the plate configuration are respectively to be disposed in such defined positions that their light output regions and light reception regions, respectively, are aligned with the light-guide layers provided in each case. This measure is attended by the advantage of simplification in the production of an optical transmission device in accordance with the invention. Specifically, the respective fixing element definitively determines the position of the optical signal output elements and the optical signal reception elements, and so adjustability is unnecessary.
It is further advantageous that given the presence of a plurality of light-guide layers in the plate configuration, at least some of the light-guide layers are optically coupled to one another by at least one optical coupling device. As a result, the light-guide layers present in a plate configuration can be optically coupled to one another to a certain extent such that, for example, one light-guide layer can be assigned only optical signal output elements, and another light-guide layer can be assigned only optical signal reception elements. It is possible to proceed in this case such that the optical signal output elements and the optical signal reception elements combined to a certain extent are respectively combined in a unit which is then inserted into the relevant plate configuration such that its light output regions and light reception regions are aligned with the various light-guide layers present.
The abovementioned optical coupling device is preferably formed by a deflecting mirror configuration, specifically by a double prism deflecting mirror configuration, in particular. This entails the advantage of a particularly low structural outlay for implementing the relevant optical coupling device.
In a concomitant feature of the invention, transmitting units are connected to the optical signal output elements, and receiving units are connected to the optical signal reception elements. The optical signal output elements and the optical signal reception elements are operated in a wavelength-specific fashion in each case in conjunction with the transmitting units and the receiving units assigned to them.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an optical signal transmission device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.